U.S. Pat. No. 4,001,742 entitled "Circuit Breaker Having Improved Operating Mechanism" describes a circuit breaker capable of interrupting several thousand amperes of circuit current at several hundred volts potential. As described therein, the operating mechanism is in the form of a pair of powerful operating springs that are restrained from separating the circuit breaker contacts by means of a latching system. Once the operating mechanism has responded to separate the contacts, the operating springs must be recharged to supply sufficient motive force to the movable contact arms that carry the contacts.
U.S. patent application Ser. No. 08/202,140 filed on Feb. 25, 1994 entitled "OPERATING MECHANISM FOR HIGH AMPERE-RATED CIRCUIT BREAKERS" describes an operating mechanism capable of immediately resetting the circuit breaker operating mechanism to reclose the contacts without having to recharge the circuit breaker operating springs immediately after opening the circuit breaker contacts.
Since the operating springs within the operating mechanism assembly are increased in force as the ampere ratings are increased to account for the higher opening and closing requirements of the circuit breaker contacts with the increased circuit current, the circuit breaker springs are usually custom-installed at the factory during the assembly of the operating mechanism components.
It would be economically advantageous to employ a common operating mechanism assembly for each of the various ampere ratings and provide a separate arrangement for assembling the operating springs without disturbing the operating mechanism assembly.
An earlier attempt to vary the circuit breaker operating springs according to the circuit breaker requirements is found in U.S. Pat. No. 4,713,508. The patent addresses the problems involved with adding the operating springs in their "charged" or compressed condition to the operating mechanism assembly at the point of manufacture.
One purpose of this invention accordingly, is to provide an arrangement whereby the circuit breaker operating springs are contained within a separate unit from the operating mechanism and can be installed within the circuit breaker enclosure without disturbing the operating mechanism assembly.